A characteristic feature of all solid-state reactions is that they involve the formation of product phase(s) at the interfaces of the reactants. Nano Crystalline Ceramic Ferromanganese nickel zinc oxide (Fe2Mn2Ni0.5Zn1.5O9) was prepared by the solid state reaction method via a high-energy ball milling process through mechanically assisted synthesis and calcined in a specially designed high temperature furnace at different treating temperatures. UV-VIS analysis of the sample was carried out. The optical constants such as refractive index, extinction coefficient, normal-incidence reflectivity, and absorption coefficient are found out. And the systematic variation of these quantities with temperature was noted. The dispersion of refractive index was analyzed by the Wemple-DiDomenico single-oscillator method. Tunable band gaps can be obtained by varying annealing temperatures.
